HMX, which is known as (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane), is the most powerful non-atomic explosive in military use, but widespread use of this explosive has been limited by its exceptionally high cost. Although HMX was first discovered in 1941, the only known process for its manufacture comprises nitrolysis of hexamethylenetetramine with a mixture of nitric acid and acetic anhydride, essentially as described by Castorina and co-workers (J.A.C.S., 82, 1617 (1960). The latter process has many deficiencies, notably there is a very poor yield of HMX on a methylene basis, and a very high consumption of acetic anhydride required during processing.
It has been proposed to produce HMX by nitrolysis of TAT, which is known as 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane. However, such attempts at this nitration have proved to be largely and very frequently unsuccessful.
These attempts have included treatment of TAT with the following, viz. (a) treatment with 100% nitric acid at temperatures ranging from -30.degree. C. to 50.degree. C.; (b) treatment with mixtures of ammonium nitrate and acetic anhydride at 70.degree. C.; and (c) treatment with mixtures of 100% nitric acid and acetic anhydride at temperatures from 0.degree. to 25.degree. C. Further techniques were used which included heavy treatment with dinitrogen pentoxide which is very expensive, or the use of phosphorous pentoxide, which is somewhat troublesome to use.
The products of the first two procedures cited above were not water-insoluble, while the third procedure produced a water insoluble product which was not even HMX. The last process utilized yielded HMX of good quality and a very slightly higher yield than the process of the art, but the reaction requires the use of elevated temperatures and very, very high amounts of very expensive reagents, such as nitrogen pentoxide and the like.